This invention relates to an image forming apparatus that forms an image onto a recording medium by moving a carriage with a recording head mounted thereon.
Conventional image forming apparatus are known to form an image onto a recording medium by moving a recording medium in a sub-scanning direction and moving a carriage mounting a recording head thereon along a guide portion in a main scanning direction.
In this type of image forming apparatus, abnormality sometimes occurs in a conveyance system of the carriage owing to various causes like foreign bodies caught in the guide portion or a failure of a driving motor of the carriage during image forming. As a result, the apparatus may not be able to operate normally. For example, a distorted image may be formed or the recording medium may no longer be conveyed. If the apparatus is in a state of abnormality, the operation of the apparatus must be stopped and the abnormality in the operation of the apparatus must be notified to the user. Thus, prompt detection of abnormality is essential.
Therefore, for example, an image forming apparatus has been proposed which detects the position of a carriage on a guide portion and determines whether a conveyance system of the carriage is normal based on information on the detected position so as to detect abnormality of the apparatus.